1. Field of the Invention
The present invention refers to a sealing assembly for a watertight fuel-gauge housing, more specifically to an improved, more efficient fuel-gauge housing for use in the automobile industry particularly designed to better suit to the harsh conditions it is submitted to when in use.
2. Description of the Prior Art
Typically a watertight fuel-gauge for use with a motor vehicle comprises a housing designed to be at least partially positioned in the interior of the fuel tank, the housing being provided with mounting flanges that cooperates with matching mounting projections in the tank. A gauge mechanism is mounted within said housing, the mechanism comprising a resistor, a cursor acting upon said resistor, said cursor being one end of an arm which opposite end is fixedly mounted to a shaft to rotate therewith, one end of said shaft projecting through an opening formed on the housing and connecting to one end of a rod which opposite end has a floating device mounted thereto.
As the position of the floating device varies according to the level of the fuel within the tank, said rod is forced to rock, which rocking rotates the shaft within the housing, the arm attached thereto and, consequently, the cursor acting against the resistor, thereby providing an indication of the level of fuel within the tank.
The opening in the housing through which said shaft projects is covered with a sealing assembly, to provide a watertight gauge, said sealing assembly typically comprising one or more “O” shaped rings positioned on the inner perimeter of the opening through which said shaft projects.
Notwithstanding the wide use of watertight gauges having a construction as described above, this structure is not totally satisfactory because usually said “O” shaped rings do not have enough dimensional compatibility with the shaft. Typically said rings will have an inner diameter bigger than the outer diameter of the shafts, therefore allowing the fuel to leak into the interior of the housing which may damage the resistor/cursor mechanism. Also, the material of the rings may yield with time giving birth to the same problem. On the contrary, when the inner diameter of the rings is smaller than the outer diameter of the shafts, this may stop the rotating movement of the shafts thereby affecting the operation of the fuel-gauge.
Another serious problem with the above mentioned “O” shaped sealing rings generally used to seal the housing of a fuel-gauge having the above construction is that they inflate and expand in the presence of fuel and this may cause them to prevent the shafts from rotating and thereby affect the operation of the fuel-gauge.